Omcan has a number of manual meat slicers with a 12" blade: they have light, medium, and heavy duty models available. Some are gear driven, some are belt driven. Some are part of their Economy meat slicers (which were made in China); others are their "Elite" series (which were made in Italy).
There is also the difference between their gravity-feed slicers and their horizontal slicers. Some of these models are capable of slicing a small amount of cheese, and other can slice cheese for hours. Check out the information below and the spec sheets for more information.